If the substrate is made of a different material than the at least one web, then mechanical stresses may occur between the substrate and the web or the seismic mass due to different thermal expansion coefficients. However, such stresses may also occur because the web and the seismic mass are already manufactured with inherent stresses. In addition, mechanical stresses in the substrate itself may be caused by the manufacturing process, by soldering or gluing or capping, for example. Since the web and the seismic mass are the clearly weaker elements compared to the substrate, these stresses are reduced by the fact that the web and the seismic mass deform, thereby changing the position of the seismic mass relative to the substrate and other fixed elements anchored on the substrate. For example, in the case of capacitively operating acceleration sensors a zero point error for the measured capacitance occurs due to a distance change of mobile electrodes to fixed electrodes.
German patent document DE 196 39 946 discusses a micromechanical acceleration sensor having a surface-micromechanical structure including two closely adjacent suspension points between which there is a movable seismic mass which is suspended at the two suspension points with the aid of suspension springs.
German patent document DE 19523895 A1 discusses a micromechanical yaw rate sensor having a surface-micromechanical structure including a central suspension (central suspension point) and a seismic mass situated around it which is suspended on the central suspension with the aid of suspension springs.
German patent document DE 19500800 A1 (FIGS. 5 & 6) discusses in FIGS. 5 and 6 a micromechanical sensor having a central suspension and two adjacent seismic masses facing one another which are connected to one another via connecting webs and suspended on the central suspension.
European Patent Application EP 1083144 A1 discusses a micromechanical device having a central suspension and two adjacent seismic masses facing one another which are connected to one another via connecting webs and suspended on the central suspension with the aid of a connecting web. The central suspension is situated in the center (on the central axis of the center of gravity or surface) of the entire movable structure.
European Patent Application EP 1626283 A discusses a micromechanical device having a central suspension and two adjacent seismic masses facing one another which are connected to one another via connecting webs and suspended on the central suspension with the aid of a connecting web. The central suspension is situated in the center (on the central axis) of the entire movable structure. Furthermore, a plurality of movable electrodes and additionally a plurality of fixed electrodes on the movable structure are disclosed.
The plurality of fixed electrodes has a shared suspension which is situated in proximity to the central suspension. Patent Application DE 10 2006 033 636 (not a prior publication) discusses a similar object.